2. All the DSLRs do.

3. It doesn't always work the same as with film cameras

Some digital cameras limit long exposures to 30 seconds or so. For some cameras, this can be overridden with an accessory cable or remote shutter release.

Another thing to keep in mind is that digital cameras will typically accumulate digital artifacts if the shutter is left open too long due to thermal signal, which is why some cameras have a long exposure noise reduction feature.

If you want to take seriously long exposures, minutes, then you're going to need to optimize dark frame subtraction, a lot of cameras will do DFS automatically in camera for longer exposures than a second or two but you can do a better job outside of the camera with software.

I've done bulb exposures with a Canon 350D, there is a port on the side of the camera you plug a remote shutter button into, it's possible to buy automated remote shutter buttons also that will program long exposures or a series of them.

6. Thanks!.I'll mostly use the bulb setting for Astronomical stuff. My personal opinion is the camera..

...people are missing out on a lot of sales.
There's quite a few Amateur astronomers who usually buy a separate camera for doing shots thru their
telescope. Needless to say, these "Special" cameras are really not that special except they have a "B"
setting and a cheap holder. ...and just about anybody could make a holder IF their present camera had the B setting. AggggH!